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Minnesota residents study pesticide drift from potato fields

FRAZEE, Minn. - Norma Smith knew something wasn't right when, after several years of successful breeding, her family's flock of nearly 70 sheep produced just six lambs. More were born the next year, but many of those were sick or deformed. By that winter, 29 of the sheep had mysteriously died.

Other strange things were happening: The Smiths would come home from church on Sunday to find dead birds in their yard. And the long familiar summer sound of frogs croaking and chirping? Suddenly silent.

The family, which lives near Frazee, had only one clue about what was going on: potato fields.

The Smiths' troubles began in 1996, one year after potato fields started sprouting up in the area, including right next door to their property.

The fields were being sprayed with chemicals at least once a week, Norma said. The timing was too suspicious for her to ignore.

The family eventually found others in the area who shared their concerns. They formed a group called Minnesotans for Pesticide Awareness, and later partnered with the Pesticide Action Network out of California to study pesticides in the air.

Over the summers of 2006 to 2009, the group took 340 air samples from 19 locations in central Minnesota, including three sites in Perham - two in rural areas and one on the southwest side of town in a residential neighborhood.

The results, recently released in a report, found various pesticides in small percentages. Traces of one chemical in particular - chlorothalonil, a fungicide commonly used on potatoes - were found in a high percentage of the samples (64 percent of all air samples taken around the state).

The percentage was much higher in the Perham area, where traces of chlorothalonil were found in 100 percent of samples taken at the first site in 2008, and 91 percent at the second site.

The third site, in town, was tested in 2009 and came in at 96 percent. All locations were within one mile of a potato field.

Other pesticides detected in the air around Perham included the herbicide chlorpyrifos, used on a variety of crops such as corn and soybeans.

Residents involved in the study are now calling for stronger protections from chlorothalonil. They say the potential health and environmental risks are understudied.

Chlorothalonil is classified by the Environmental Protection Agency as a "probable" carcinogen. Along with cancer, other health impacts from exposure include immunological reactions in the airways and skin, pneumonia and kidney failure.

Chlorothalonil is applied to 83 percent of the state's potato fields, according to information from the Pesticide Action Network. Potato fields cover roughly 50,000 acres of Minnesota, particularly in the northern Red River Valley, a small part of the southern border, and areas with sandy soils from Elk River to Park Rapids.

John Peckham, supervisor of the pesticide and fertilizer management division's inspection unit at the Minnesota Department of Agriculture, said chlorothalonil is used by potato growers to help fight off late blight, "a very difficult, deep disease to control."

In March, the EPA began a new review of chlorothalonil, which will include inhalation studies.

An entire report of the study and its results, "Pesticide Drift Monitoring in Minnesota," may be found online at www.panna.org.